mershoff



R. D. MERSHON. ELECTRIC MOTOR, GENERATOR AND OTHER APPARATUS.

APPLIOATIOH FILED D110. 3 190B.

Patented Apr. 5, 1910.

Wiin 95898: 7%. M 7- R. D. MERSHON.

ELEOTBIO MOTOR, GENERATOR, AND OTHER APPARATUS APPLICATION FILED 1130.3, 1906.

953,749. Patel lted Apr. 5, 1910.

Evy 9 3 SHEETS-SHEET 2- M lnv n I R. 1). MERSHON. ELECTRIC MOTOR, GENERATOR, AND OTHER APPARATUS.

APPLICATION FILED DEC. 3, 1906.

Patented A pr. 5, 1910.

3 SHEETS-SHEET 3.

ma; i i- L: R

Riii i- Inverzfor RALPH D. MERSHON, OF NEW YORK, N. Y.

ELECTRIC MOTOR, GENERATOR, AND OTHER APPARATUS.

Original'application filed February 1-, 1904, Serial No. 191,464.

Serial No. 346.094.

' f all whom 'it may concern:

Be 1t known that I, RALPH D. MunsnoN,'

a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Electric Motors, Generators, and other Apparatus, of which the following is a specification, reference being bad to the drawings -accompanying andforming part of the same.

The lnvention which forms the subject of the present application (which 1s a (l1v1s1on of my earlier application Ser. No. 191,464, now Patent N o. 842,966,-issued February 5, 1907) relates more particularly to the obtaining of any desired speed,.in motors, and

any desired frequency, in generators, whether of the induction or synchronous type, though the invention is applicable as well toother apparatus in Which-magnetic poles are produced, as will appear more clearly from the detailed'cxplanation given hereinafter. Nor is the application of the invention limited to any particular type of apparatus, whether single phase orpolyphase, or to any particular kind of windings, whether irramme ring or drum, uniformly or non-uniformly distributed, etc, but it applies to any winding which willlend itself to the production of the desired angle between poles. For the sake of convenience and brevity, however, the description of the invention will be con lin-ed to the case of its application'to a single phase induction machine with a uniform ring winding.

It is usual, in alternating current apparatus, to consider that. the speed, or the frequenoy, depends upon the number of poles in the exciting or energizing element, and that a closed, or complete, system of poles mustbe used; and heretofore, so far as I am aware, only an even number of poles, that is, two or a multiple of two, and a closed system of poles, have been considered in this connection. Hence the obtaining of difi'ercnt speeds and frequencies by variation of the number of poles, either bychange in the design of the apparatus or by changing the ointsof connection, or otherwise chang- 1ng the connection in any way, when the constructionof the apparatus permits such manipulation, is confined to closed systems of poles and to speeds or frequencies corrc-' Specification of Letters Patent. I

Patented Apr. 5, 1910.

Divided and this application filed December spending to pole-numbers differing by at least two. This difference may sometimes be greater than isdesirablc. For example, a motor having 4: poles, operated by currents having a frequency of 3600 alternations per minute, will have asynchronous speed of 900. If the number of poles be increased to '(l, the synchronous speed will then be 600, and. if the number be reduced to 2, the synchronous speed will be 1800. The difference in the two cases is 300 and 900 respectively, and it may often happen that these variations are too large for the purposes intended. It is therefore desirable to have some method by which practically any difference may be obtained, thereby securing a more convenient control. ofspe'cd or frequency. Itmay also at times be desirable to reduce the number of leads to the apparatus even for speeds or frequencies corresponding to an even number of poles,'and which would therefore admit of a-closed system of poles. This is especially the case with some forms of windings,'which are inherently such that the production of certain even pole-numbers would greatly multiply the number of leads to the apparatus. v

To provide a method which will accomplish these results is the object of my present invention.

- lhe same consists in the novel feature of construction, arrangements of parts and combinations of elements hereinafter described and more particularly set forth in the claims.

It will be more easily understood when explained 'inconnection with the accompanying drawings, in which t Figure 1 represents diagrammatically a uniformly distributed Gramme ring winding and the connections for sixteen poles; Figs. 2 and 3 show the same element, but with some of the connections, and consequently the corresponding poles, omitted, the re- "maining connections and poles being as before." Fig. 4 shows a similar winding, with the equivalent of two poles, and Fig. 5 with the equivalent of threepoles, so far as speed or frequency is concerned. Fig. 6 shows another arrangement for the equivalent of two and two-thirds poles, giving a corresponding speed or frequency. Fig. 7 shows an arrangement for the equivalentof nine poles,

y from the plane of the figure.

and Fig; 8 another arrangement for the sa mo purpose.

the connections of its coils from that of the previous figures, and gining an equivalent of twelve and one-half poles. Here the con nections are for convenience of illustration shown brought out to a system of contacts in a manner somewhat similar to that in which the leads from a direct current arma; turn are brought out to the commutator segments. The arrows applied to the contacts show thedirection of the currents supplied to the winding and the points at which they enter the same. The arrows around the cir' cumference of the ring show the directions of the magnetizing forces in the coils to which they correspond due to the currents in the coils. If the ring shown he say, the primary of an induction motor, the secondary may be considered as outside ofthe ring, or if the secondary be considered as inside the ring, the various leads inside the ring would be considered as removed to the outside or as displaced a suflicient distance Figs. 10 and 11 show the relative positions of the poles in apparatus with four and six poles respectively. Fig. 12 shows in diagram a single phase system. arranged for changing from six or eight-poles to the equivalent of seven poles to obtain the intermediate speed corresponding thereto. In the latter case the poles are produced in groups.

It may be noted that Figs. 1 and 4: show closed systems of poles since the poles alternate in sign and are spaced equidistantly around the whole of the circumference; while in arrangements such as indicated in Figs. 2, 3,5, 6, 7, 8 and 9 the poles do not necessarily alternate in sign throughout, nor occupy the whole of the circumference, the result being an open system of poles in each case. I

Referring now to Figs. 1 and 2, it will be seen that the latter is the same-as the former with the exception that six poles are omitted- Nevcrtheless the angles between the remainin olcs are the same and therefore thesynchronous speeds or frequencies are the same- This follows from the fact that a conductor moving with the same speed through the fields of poles 7, 8, 9, 10, 11 and 15, 16, 1, 2, 3,, will be affected with the same frequency whether it be moving in Fig. 1 or in Fig. 2. Conversely, with the same frequency in each example, the syn.- chronous speed would be the same in both cases. It therefore follows, as previously stated, that the angle between the poles is the determining factor of synchronous speed or of frequency. If the principles be applied to the ordinary form of generators and motors of the synchronous type,

Fig. 9 is a diagram showing a ring wiuding differing in the manner of the interference occurs.

whether the poles are salient or not, but in which, in general, the coils of the other element embrace angles ap roximately that of the pole pitch, there wi 1 be a tendency for poles to be inducedpby the currents in the other element, at the points .where excitation suppressed, and such induction will result unless the field structure be suppressed at these points; but whether the latter be suppressed or not, and if the poles he induced, the principle of my invention is in no way invalidated. Tn structures-of the induction type. in which the circuits of the other element cmb ace angles in general considerably less than the polar pitch, this in-u (luctive effect will extend slightly beyond the excited portion of the exciting element.

It the clireults of the other element embrace angles ap -iroxiinately equal to the polar pitch, this inductive effect may. as in the previous case, extcndbcyond these poles, but, as previously stated. in such case the principle of my Invention is in no way invalidated. Bearing in mind then/that the.

speed or frequency depends upon the angular spaclng of the poles, the apparatus shownin Fig. t will have a synchronous integral number of poles two poles of the same sign'fall adjacent to each other. \Vhen their proximity becomes such that they will in any way interfere, either in the exciting winding or in the winding of the other" element, as many poles, one or more, as necessary, may be omitted at the place where For example, Fig. 8 shows the nine-pole connection with one of the north poles of Fig. 7 omitted.

In some cases, as for instance in the case of two circuit multipolar drum or ring windings, it may be necessary or desirable to have the poles in groups, one or more poles being omitted between roups. An example of this is shown in Fig.9. Here an odd number of coils is used, which of itself prevents the use of an integral number of poles deads are and therefore the use of a closed system of although .it might for others, if it had an even number of coils divisibleby thenumber of poles required. An examination of Fig. 9 will show that coils approximately oppo site will, if the proper terminals be chosen, be in series' This means that the relation between the poles to which these two coils contribute is fixed so long as the series con- ,nection of the coils is employed For instance, by reference to the figure it will'be,

seen that poles of the .same sign are approxir mately opposite; if the number of coils were I even such' poles might be exactly opposite.

Now the conditionof. poles of the same sign at opposite ends of a diameter is one which answers for some numbers of poles but not for others, as will be'flseen on comparing Figs. 10 and E 11, re resenting apparatus similar to that alrea y described, Fig. 10-

. fore, with a winding connected similarly to.

-- site coils in Fig. 9, poles of thesame size will come eX- actly opposite, instead of approximately opposite, as in Fig. 9), it will be'impossibleto obtain pole numbers other than those in which poles of the same'sign are'opposite unless opposite coils be used in other than their series connection, which'will necessitate a greater number of leads to the apparatus. In such a winding, therefore, in order to keep down the number of leads, 'it might at times be desirable to use the oppotheir series connection, and in order to do so for the speeds or frequencies corresponding to pole numbers other than those in which poles of the same sign come opposite, it would be necessary to operate with the poles in two or more groups as in Fig. 9, the groups being separated by an unexcited portion of the element. This explanation, which has been made with reference to a winding iifn'liicli the coils connected in. series are opposite or approximately opposite, holds for the series connection of coils bearing any other definite fixed relation, as for instance where the coils are arranged at intervals of ninety degrees.

In Fig. 12 is shown a system, which for the sake of simplicity in the diagram is shown as for single phase and with a uniformly distributed ring winding, adapted for change in the number of its poles by change in the points at which the current or currents are led into the winding. By tracing out the connections through the controller, diagrammatically represented at C, itwill be seen that in the first position, indicated by I, current will be supplied to the motor forth.

by leads l--4,-'6'-9'-'12-14, each 130 apart and therefore producing Si'X oles. In the next position,"'indicated by II, eads 2-58 ;of one group are 51 3/7 apart,

and leads 10l3-16.; of,another group are also 51. 3/7 apart,,- giving a speed equivalent to seven poles. In the next position, indicated by III, the current is fed through leads l-3-5'7 9--11.-131 5,'

whichare 45 apart, giving eight poles. In-

the "intermediate speed corresponding to seven poles, by omitting one lead from the possible total of seven leads, and arranging the two groups ofthree each with themiddle 'lead of each group on a diameter, the total number of leads is reduced, since by so arranging them not only has the one leadmentioned been omitted, but it has also beenmade possiblertouse leads 5' and 13, which'are employed in the 8-pole connection. The same principles apply of course to polyphase apparatus, and to windingsother than the ring form or those which-are uniformly distributed.

It will be understood, of course, that while for the sake of simplicity the invention has been described inconnection with apparatus having only one lead per pole, it may be applied as well in connection with my method of obtaining a desired magnetic flux distribution wherein more than one lead per pole is em loyed, as more fully described, and claime broadly','in my -copend-- ing application, Serial Number 17 L698.

What I claim is:

l. .Thecombination of an alternating cur.- rent machine having a primary elementpro 'vided with leads for consecutive even numbers of poles and for poleswhose angular spacing is intermediate thereto, and a controller in circuit with said l eads'," asrse't 2. The combination of an alternating current machine having a primary element pro vi-ded with leads for a given number of' poles with given angular spac1ng,'andw1th additional leads, whereby the same'number ot poles maybe produced with different angular spacing, and a controller in circuit with said loads, as setforth. a

3. The combmatron'of an alternating current apparatus in which'the speed or'frequency depends uponthe spacing of the poles, an external circuit, and means forconnecting the apparatus with the said circuit to produce in the former as regards speed or frequency an effect-corresponding to the spacing. 0 an oddv or non-integral number of poles, as set forth.- 1

4. The combination of an alternating current machine having a primary element p'ro'- vided with'leads for producing poles with bers of poles and for producing poles with angular spacing corresponding to even num 1 ing a primary element provided with leads connected thereto at points to produce poles with angular spacing corresponding to an odd or non-integral number of poles, as set forth. a

6. An alternating current machine having a. primary elementprovided with leads-for producing poles With-angular spacing corresponding to even numbers of poles and for producing poles with. angular spacing corresponding to an odd or non-integral num her'of poles, as set forth. 7 The combination of an alternating current motor havil'u a primary element provided with leads or consecutive even numbers of poles and for poles whose angular spacing isintermediate thereto, and a controller in circuit with said leads, as set forth. a

8. The combination of an alternating current motor having a primary element pro vidcd with leads for a given number of poles with given angular spacing, and with additional leads, whereby the same number ofpoles'may be pr'pduced with difi'erent angular spacing, and a controller in circuit with said leads, as set forth.

9. The combination. of an alternating current motor in which the speed depends upon the spacing of the poles, an external cir-. cuit, and means for connectin the motor with the said circuit to pro uce in the former as regards speed an effect equivalent to the spacing of an odd or non-integral number of poles, as set forth.

10. The combination of an alternating current motor liaving'a primary element provided with leads for producing poles with angular spacing corresponding'to even numbers of poles and for producing poles with angular spacing; corresponding to an odd or non-integral number of poles, and means for variably connecting the motor with an external circuit, as set forth.

11. An alternating current motor having a primary element provided with leads connected thereto at points to produce poles with angular spacing corresponding to an odd or non-integral number of poles, as set forth.

12. An alternating current motor having a primary element provided with leads for producing poles with angular spacing corresponding to even numbers of poles and for producing poles with, angular spacing corresponding to an odd-or nonintegral num ber of poles, as setforth.

13. The combination of an induction motor having a primary element provided with leads for pro leads for-consecutive even numbers of poles and for poles whose angular spacing is intermediate thereto, and a controller in cirsuit with said leads, as set forth.

14:. The combination of an induction mo- .tor having a primary element provided with leads for a given number of poles with given angular spacing, and with additional leads, whereby the same number of poles may be produced with different angular s acing, and a controller in circuit with sai leads, as set forth.

1 5. The combination of an induction motor having a (primary element provided with ucing poles with angular spacing corresponding to even numbers of poles and for producing poles with angular spacing corresponding to an odd or nonintegral number of poles, and means for variably connecting the motor with an external cir' cuit, as set forth.

. 16. An induct-ion motor having -a primary element 'rovided with leads connected thereto at points to produce poles with angular spacing corresponding to an odd or nonintegral number of poles, as set forth.

17. An induction motor having a primary element provided with leads for producing poles with angular spacing corresponding to even numbers of poles and for producing poles with angular spacing corresponding to an odd or non-integral number of poles, as set forth,

18. In combination, an induction motor having a primary winding provided with terminal connections for producing diiferent pole numbers and intermediate taps between said terminals, and a controlling-switch in circuit with said taps.

19. In combination, an induction-motor having a primary Winding provided with terminal connections for producing diflerent pole numbers and intermediate taps between said terminals, and a controlling-switch adapted to connect either set of terminals or the intermediate taps to a source of current.

20. In combination, an induction-motor having a primary winding provided with terminal connections for producing dilferent pole numbers and intermediate taps between said terminals, and a controlling-switch having its contacts arranged to connect a set of terminals for one number of poles to a source of current, then to break said connections and to connect the intermediate taps successively to the source, .and finally to i connect. the terminals for the second number of poles to the source.

. 21. In combination, an induction-motor having a primary winding provided with terminal connections for producing difi'erent pole numbers, and intermediate taps unsyminetrically arranged between said terminals,

and a controlling-switch adapted to connect either set of terminals or said taps to a source of current.

22. In combination, an induction-motor I having a primary winding provided with terminal connections for producing two different pole numbers and intermediate taps corresponding in number to the terminals for the smaller number of poles-but unsymmetrically placed, nude switch adapted to connect either set of terminals or said taps to a source of current.

RALPH D. 'lvlEl'isHON.

Witnesses:

M. LAWSON DYER,

S. S. DUNHAM. 

